Transportation equipment such as trucks, cars, boats and the like are operated by a driver or an operating crew for extended periods of time without direct supervision. Accordingly it is common to install recording devices on these vehicles for supplying visible recordings of the various operating parameters such as driving speed, motor rpm and on/off conditions for brakes, heaters, power takeoff, etc. The recordings are usually made by stylii which record the parameters such as driving speed or engine rpm on a recording receiving medium which is generally in the form of a circular disk or a paper tape. The recording medium is moved by a clock mechanism with constant speed and will usually include a network imprint such as a network of scales having time markings which move in the direction of movement of the recording medium. The time markings are arranged for recording of the parameters by the stylii at the correct time of their occurrences and in order to meet this requirement the recording medium must be inserted in the recording device such that the recordings start with insertion of the recording medium at the correct preprinted time markings of the scale. Since the recording medium and the drive system are often designed in a manner such that the recording medium can only be inserted when the drive system is in a certain position it is necessary to provide an adjustment system which allows adjustment of the relative positions of the recording medium and the stylii.
This adjustment system is accessible to any personnel who have to tend to the recorder for inserting and removing the recording medium which leads to the possibility of the operating personnel manipulating the position of the recording medium. These personnel can, therefore, falsify the recordings by recording inaccurate times in which the conditions occur and/or by recording prolonged and shortened time periods for the conditions.